Police in France have searched a property believed to be the home of a known terror suspect who shot dead one police officer and seriously wounded two more in an attack two days before voting begins in an already tense presidential election.

Police in France have searched a property believed to be the home of a known terror suspect who shot dead one police officer and seriously wounded two more in an attack two days before voting begins in an already tense presidential election.

The gunman stepped from a car and opened fire on a police van with an automatic rifle outside a Marks & Spencer store on the Champs Élysées in central Paris at about 9pm on Thursday.

The gunman stepped from a car and opened fire on a police van with an automatic rifle outside a Marks & Spencer store on the Champs Élysées in central Paris at about 9pm on Thursday.

The attacker, a 39-year-old man widely named named as Karim Cheurfi, was known to French security services. Media reported he had served nearly 15 years in prison after being convicted of three attempted murders – two against police officers – in 2001.

The attacker, a 39-year-old man widely named as Karim Cheurfi, was known to French security services. Media reported he had served nearly 15 years in prison after being convicted of three attempted murders, two against police officers, and was released on parole in 2015.

He was shot dead by police while trying to flee on foot. A statement from the Isis propaganda agency, Amaq, said the attack was carried out by an “Islamic State fighter”.

The attacker was shot dead by police in the van while trying to flee the scene on foot. A statement from the Isis propaganda agency, Amaq, said the attack was carried out by an “Islamic State fighter”.

After a series of atrocities that have killed more than 230 people in France over the past two years, authorities had long feared bloodshed in the run-up to polling day and observers have speculated the attack could bring security to the forefront of voters’ concerns in Sunday’s first round.

After a series of atrocities that have killed more than 230 people in France over the past two years, authorities had long feared bloodshed in the run-up to polling day and observers have speculated the attack could bring security to the forefront of voters’ concerns in Sunday’s first round.

The prime minister, Bernard Cazeneuve, said the government had reviewed its extensive election security measures and was “fully mobilised” in the wake of the attack.

The US president, Donald Trump, tweeted on Friday that the attack would have a “big effect” on the election, adding: “The people of France will not take much more of this.”

“Barbarity and cowardice struck Paris last night, as they also recently struck elsewhere in Europe in Berlin, Stockholm, in London,” Caeneuve said after a meeting of its security council on Friday. “The whole of Europe is being targeted, because it represents the values and ideals of peace”.

But the prime minister, Bernard Cazeneuve, said the government had reviewed its extensive election security measures and was “fully mobilised” in the wake of the attack. He appealed for national unity and for people “not to succumb to fear”.

He said more than 50,000 police and gendarmes and 7,000 soldiers would be on duty for Sunday’s first-round vote in the two-stage election, and nothing could be allowed to “hamper this democratic moment”. He appealed for national unity and for people “not to succumb to fear.”

Cazeneuve said after a meeting of France’s security council on Friday: “Barbarity and cowardice struck Paris last night, as they also recently struck elsewhere in Europe in Berlin, Stockholm, in London. The whole of Europe is targeted, because it represents the values and ideals of peace”.

A house in the eastern suburb of Chelles, believed to be Cheurfi’s family home, was being searched on Friday. Le Parisien newspaper said the address matched that of the owner of the car used in the attack. Police had found a pump-action shotgun and knives in the vehicle.

He said more than 50,000 police and gendarmes and 7,000 soldiers would be on duty for Sunday’s first-round vote in the two-stage election, and nothing could be allowed to “hamper this democratic moment”.

Police sources told French media Cheurfi was arrested in February on suspicion of plotting to kill police officers but released because of lack of evidence.

A house in the eastern suburb of Chelles, believed to be Cheurfi’s family home, was being searched on Friday. Le Parisien newspaper said the address matched that of the owner of the car used in the attack.

He was reportedly not, however, on France’s “Fiche-S”, the list of people suspected of being a threat to national security.

Police found a pump-action shotgun, knives and a Qur’an in the vehicle, while a handwritten note praising Isis was later recovered near the dead attacker, police sources told local media.

Isis named the attacker as Abu Yusuf al-Beljiki, or “the Belgian”, but it was not clear if the statement referred to Cheurfi. The Belgian interior minister, Jan Jambon, said he was “certainly not the guy who committed the crime yesterday”.

They said Cheurfi was arrested in February on suspicion of plotting to kill police officers but released because of lack of evidence. He was reportedly not, however, on France’s “Fiche-S”, the list of people suspected of being a threat to national security.

A Belgian national sought earlier by Belgian police and thought to have travelled to France on Thursday turned himself in to police in Antwerp, a French interior ministry spokesman, Henri Brandet, said on Friday.

Isis named the attacker as Abu Yusuf al-Beljiki, or “the Belgian”, but it was not clear if the statement referred to Cheurfi. The Belgian interior minister, Jan Jambon, said he was “certainly not the guy who committed the crime yesterday ... The guy who yesterday did the act was not a Belgian. He was French.”

A source close to the French investigation said the 35-year-old Belgian man, described as “very dangerous”, had been sought by his country’s police force as part of a separate investigation. Hours before the Paris assault, Belgian police reportedly found weapons, balaclavas and a ticket for a train trip to France departing on Thursday morning.

A Belgian national sought earlier by Belgian police and thought to have travelled to France on Thursday turned himself in to police in Antwerp, a French interior ministry spokesman, Henri Brandet, said earlier on Friday.

A source close to the French investigation said the 35-year-old Belgian man, described as “very dangerous”, had been sought by his country’s police as part of a separate investigation. Hours before the Paris assault, Belgian police reportedly found weapons, balaclavas and a ticket for a train trip to France departing on Thursday morning.

Belgian prosecutors said the man handed himself in “after he saw himself appear on social media as terror suspect No 1”, but that he had nothing to do with the attack. The Belgian justice minister, Koen Geens, said on Friday the government had “no information at this moment about Belgian links”.

Belgian prosecutors said the man handed himself in “after he saw himself appear on social media as terror suspect No 1”, but that he had nothing to do with the attack. The Belgian justice minister, Koen Geens, said on Friday the government had “no information at this moment about Belgian links”.

In France, three people known to Cheurfi were arrested during overnight raids in the eastern suburbs of Paris and were being questioned by anti-terror police, judicial sources said.

In France, three people known to Cheurfi were arrested during overnight raids in the eastern suburbs of Paris and were being questioned by anti-terror police, judicial sources said.

The outgoing president, François Hollande, paid tribute to the police on Thursday night and pledged “absolute vigilance, particularly with regard to the electoral process”, taking place under a national state of emergency which has been in place since 2015.

The outgoing president, François Hollande, paid tribute to the police on Thursday night and pledged “absolute vigilance, particularly with regard to the electoral process”, taking place under a national state of emergency that has been in place since 2015.

The interior minister, Matthias Fekl, said: “The sense of duty of our policemen tonight averted a massacre … they prevented a bloodbath on the Champs Élysées.” A female foreign tourist was also slightly wounded in the attack.

The interior minister, Matthias Fekl, said: “The sense of duty of our policemen tonight averted a massacre … they prevented a bloodbath on the Champs Élysées.” A female foreign tourist was also slightly wounded in the attack.

It is difficult to predict the impact of the attack on the election, which polls suggest is too close to call. How the candidates judge the public mood and what they say in response could well influence their chances.

It is difficult to predict the impact of the attack on the election, which polls suggest is too close to call. How the candidates judge the public mood, and what they say in response, could well influence their chances.

Three of the frontrunners – the far-right leader Marine Le Pen, independent centrist Emmanuel Macron and scandal-hit conservative François Fillon – cancelled events on Friday, the final day of campaigning.

Three of the frontrunners – the far-right leader Marine Le Pen, independent centrist Emmanuel Macron and scandal-hit conservative François Fillon – cancelled events on Friday, the final day of campaigning.

Le Pen, whose key themes during the campaign have been increased security and border controls and tougher treatment of flagged radicals in France’s fight against Islamist extremism, called for “a clear head and a firm grip” in the wake of the attack, telling RTL radio that it was “time to stop being naive”.

Le Pen, whose key themes during the campaign have been increased security and border controls and tougher treatment of flagged radicals in France’s fight against Islamist extremism, called for “a clear head and a firm grip” in the wake of the attack, telling RTL radio that it was “time to stop being naive”.

She called for France to immediately take back control of its borders from the EU and deport all foreigners on a terror watchlist. “This war against us is ceaseless and merciless,” she said.

She called for France to immediately take back control of its borders from the EU and deport all foreigners on a terror watchlist. “This war against us is ceaseless and merciless,” she said.

Macron said attackers wanted “death, symbolism, to sow panic and to disturb a democratic process, which is the presidential election”. Asked if the assault would impact voting, Macron said: “No one knows.”

Macron said attackers wanted “death, symbolism, to sow panic and to disturb a democratic process, which is the presidential election”. Asked if the assault would impact voting, Macron said: “No one knows.”

He said if he was elected he would swiftly create a special taskforce to coordinate French intelligence efforts against Islamic State, and accused Le Pen of lying when she claimed she could have prevented previous attacks if she had been in office. “She won’t be able to protect our citizens,” he said.

He said if he was elected he would swiftly create a special taskforce to coordinate French intelligence efforts against Islamic State, and accused Le Pen of lying when she claimed she could have prevented previous attacks if she had been in office. “She won’t be able to protect our citizens,” he said.

Fillon said France had to show it was “united and not afraid” against an Islamic radicalism that “defies our values”. The country was “in a long war against an enemy that is powerful, whose networks are numerous and whose followers live among us, next to us,” he said. “They want to destroy our civilisation ... but certain people have not taken into account the evil they represent.”

He pledged to maintain the state of emergency and said the “fight for the French people’s freedom and security will be mine”.

The Champs Élysées reopened on Friday, having been sealed off for much of Thursday night as police ordered tourists back into hotels and blocked people from approaching the scene. Emergency vehicles blocked access and metro stations were closed.

The Champs Élysées reopened on Friday, having been sealed off for much of Thursday night as police ordered tourists back into hotels and blocked people from approaching the scene. Emergency vehicles blocked access and metro stations were closed.

France has been on its highest possible level of terror alert since the 2015 Charlie Hebdo and Paris attacks and the Nice truck attack of 2016. Thousands of troops and armed police have been deployed to guard tourist hotspots, such as the Champs Élysées.

France has been on its highest possible level of terror alert since the 2015 Charlie Hebdo and Paris attacks and the Nice truck attack of July 2016. Thousands of troops and armed police have been deployed to guard tourist hotspots, such as the Champs Élysées.

This week, two men were arrested in Marseille on suspicion of planning an attack before the election. A machine-gun, two handguns and 3kg of TATP explosive were found at a flat in the southern city, along with Isis propaganda material.

This week, two men were arrested in Marseille on suspicion of planning an attack before the election. A machine-gun, two handguns and 3kg of TATP explosive were found at a flat in the southern city, along with Isis propaganda material.

Polls have suggested Le Pen and Macron are the most likely candidates to go through to the second-round runoff on 7 May, but Fillon and the hard-left candidate Jean-Luc Mélenchon are only two or three points behind, and up to 25% of voters have yet to make up their minds, meaning any two of the four could qualify.

Polls have suggested Le Pen and Macron are the most likely candidates to go through to the second-round runoff on 7 May, but Fillon and the hard-left candidate Jean-Luc Mélenchon are only two or three points behind, and up to 25% of voters have yet to make up their minds, meaning any two of the four could qualify.